Transcript Introduction

Introduction

Recently, more and more plasma displays are marketed.
They have wide screens, comparable to the largest CRT
displays, but they are only about 15cm thick. The basic
idea of a plasma display is to illuminate tiny colour
fluorescent lights (called pixels) to form an image. Each
pixel is made up of three subpixel cells with different
fluorescent lights -- a red light, a green light and a blue
light. By varying the intensities of these three colors, A
full range of colors are produced in each pixel. Then the
image is formed when these pixels light up.
Plasma Display
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TianHua Zhang
Inside the display
Plasma
An electrically neutral, highly ionized gas composed
of ions, electrons, and neutral particles.
Xenon and neon atoms are used in plasma
displays.These atoms release ultraviolet light photons,
which are invisible to the human eye. But these UV
photons can excite visible photons.
Inside the display
photoluminescent
phosphors
Red
(Y,Gd)BO3:Eu+3
Green
Zn2SiO4:Mn+2
Blue
BaMgAl10O17:E+2
How Atoms light up
How Display work
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The intersecting electrodes are charged (with a voltage
difference between them), an electric current flows
through the gas in the cell. The current creates a rapid
flow of charged particles, which stimulates the gas
atoms to release UV photons.
How Display work
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UV photons are invisible, which interact with phosphor
material coated on the inside wall of the cell. The
phosphors give off colored light when they are excited.
How Display work
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By varying the pulses of current flowing through the
different cells, the control system can increase or
decrease the intensity of each subpixel color to create
hundreds of different combinations of red, green and
blue. This process can be done thousands of times in a
small fraction of a second for each pixel in turn.
Some Comparisons
(CRT)
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They are bulky. In order to increase the screen
width in a CRT set, you also have to increase
the length of the tube (to give the scanning
electron gun room to reach all parts of the
screen). The image is not as bright as LCD and
plasma display.
CRTs give off electric, magnetic and
electromagnetic fields. There is considerable
controversy as to whether any of these pose a
health hazard, particularly magnetic fields.
Some Comparisons
(LCD)
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Display size is limited by the quality-control
problems faced by manufacturers. to
increase display size, manufacturers must
add more pixels and transistors. As they
increase the number of pixels and transistors,
they also increase the chance of including a
bad transistor in a display. about 40 percent
of the panels that come off the assembly line.
The level of rejection directly affects LCD
price.
Limited viewing angle.
Plasma display
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Advantages
1.Large screen size (up to 60
in. diagonal)
2.Thin form factor (< 4 in.)
3.Full color with good color
purity
4. Fast response time for
excellent video capability
5. Wide viewing angle
(>160o , all directions)
6. Insensitive to ambient
temperatures
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Disadvantages
1. Low luminance for
outdoor applications
(non-sunlight readable)
2. Low contrast in high
ambient light
3. High power consumption
and heat generation
4. Short panel lifetime due
to phosphor degradation
5. Latent image (Image
sticking)
References
1.
2.
3.
4.
Betsui, Keiichi., F. Namiki., Y. Kanazawa and H. Inoue. 1999.
High-resolution Plasma Display Panel (PDP).
http://electronics.howstuffworks.com/plasma-display.htm
http://mass.micro.uiuc.edu/publications/papers/77.pdf
http://en2.wikipedia.org/wiki/LCD